Abstract: An Nd:YAG laser with 1 kW average power, 180 J pulse energy, 60 kW pulse power and with 600 $mu@m diameter fiber optic beam delivery has been developed. Applications include 4.8 mm deep seam welding at 50 mm/min and 5 mm thick metal cutting at 400 mm/min. Using pulse superposition of unequal and or delayed pulses provides a simple and effective way of shaping the time profile of the pulse, which can be of advantage for special welding applications. Energy is measured on line by means of a wedged beam sampler, an integrating sphere, an optical fiber and a photodiode. Regarding the beam delivery optics, special care must be taken to minimize reflection losses. Anti-reflection coating of fiber end faces was investigated. Though the peak power density 30 MW/cm$+2$/ is lower than what has been reported as a routinely achievable damage threshold, the tremendous energy density 90 kJ/cm$+2$/ poses problems. In view of the relatively small area of the fiber, end face cleaning and surface adhesion are critical. Two high power processing head objectives were developed to image the fiber end face onto the work piece. !3
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机译：摘要：开发了一种Nd：YAG激光器，其平均功率为1 kW，脉冲能量为180 J，脉冲功率为60 kW，光纤束的直径为600μm。应用包括以50 mm / min的速度进行4.8 mm深缝焊接以及以400 mm / min的速度进行5 mm厚的金属切割。使用不相等和/或延迟的脉冲的脉冲叠加可提供一种简单有效的方式来调整脉冲的时间分布，这对于特殊的焊接应用可能是有利的。借助楔形光束采样器，积分球，光纤和光电二极管在线测量能量。关于光束传输光学器件，必须格外小心，以最小化反射损耗。研究了纤维端面的抗反射涂层。尽管峰值功率密度30 MW / cm $ + 2 $ /低于常规可达到的损坏阈值，但巨大的能量密度90 kJ / cm $ + 2 $ /却带来了问题。鉴于纤维的面积相对较小，端面清洁和表面附着力至关重要。开发了两个高功率加工头物镜，以将光纤端面成像到工件上。 ！3
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